Hi can you let me know why do you need to downgrade?
Any concern with the current version?
After upgrading ZC520TL to Oreo, it became useless. Phone lags after any action, music lags when using phone, cannot answer incoming call immediately because of lag of screen. ZC520TL was a smartphone with Nougat. With Oreo it's phone or rather just a brick
@nani30082000 Here is Marshmallow software, flash it using SP Flash Tool. I AM NOT TAKING ANY RESPONSIBILITY FOR YOUR BROKEN DEVICE! Software is working on my ZC520TL, I've flashed it yesterday and it is so much better than Oreo (copy-paste link, I can't post links)